1. J. Riofrio, E. J. Barth. “A Free Piston Compressor as a Pneumatic Mobile Robot Power Supply: Design, Characterization and Experimental Operation”. International Journal of Fluid Power, vol. 8, no. 1, pp.17-28, March, 2007.
  1. C. Yong, and E. J. Barth, “Modeling and Control of a High Pressure Combined Air/Fuel Injection System”. 2009 ASME Dynamic Systems and Control Conference and Bath/ASME Symposium on Fluid Power & Motion Control. Accepted for publication June 2009.
  1. J. A. Willhite and E. J. Barth, “Reducing Piston Mass in a Free Piston Engine Compressor by Exploiting the Inertance of a Liquid Piston”. 2009 ASME Dynamic Systems and Control Conference and Bath/ASME Symposium on Fluid Power & Motion Control. Accepted for publication June 2009.
  1. J. A. Riofrio and E. J. Barth. “Experimental Assessment of a Free Elastic-Piston Engine Compressor with Separated Combustion Chamber,” Bath/ASME Symposium on Fluid Power and Motion Control (FPMC 2008), pp. 233-244, September 10-12, 2008. Bath, U K. NOTE: Winner of the Best Paper Award for the entire Symposium.
  1. C. Yong, J. A. Riofrio and E. J. Barth. “Modeling and Control of a Free-Liquid-Piston Engine Compressor,” Bath/ASME Symposium on Fluid Power and Motion Control (FPMC 2008), pp. 245-257, September 10-12, 2008. Bath, U K.
  1. J. A. Riofrio, E. J. Barth. “Design and Analysis of a Resonating Free Liquid-Piston Engine Compressor,” 2007 ASME International Mechanical Engineering Congress and Exposition (IMECE), IMECE2007-42369, November 11-15, 2007, Seattle, WA.
  1. J. Riofrio, E. J. Barth. “Experimental Operation and Characterization of a Free Piston Compressor,” 2005 ASME International Mechanical Engineering Congress and Exposition (IMECE), IMECE2005-81743, November 5-9, 2005, Orlando, Fl.
  1. J. Riofrio, E. J. Barth. “Design of a Free Piston Pneumatic Compressor as a Mobile Robot Power Supply,” Proceedings of the 2005 IEEE International Conference on Robotics and Automation (ICRA), pp. 236-241, Barcelona, Spain, April 2005.
  1. E. J. Barth, J. Riofrio. “Dynamic Characteristics of a Free Piston Compressor”. 2004 ASME International Mechanical Engineering Congress and Exposition (IMECE), IMECE2004-59594, November 13-19, 2004, Anaheim, CA.

Free-Piston Engine Compressor

The free piston engine compressor is a device that utilizes combustion to compress air into a high-pressure supply tank. The device is configured such that the transduction from thermal energy to stored energy, in the form of compressed gas, is efficient relative to other small-scale portable power supply systems. This efficiency is achieved by matching the dynamic load of the compressor to the ideal adiabatic expansion of the hot gas combustion products. Our work shows that a load that is dominated by inertia in the early portion of the power stroke provides a nearly ideally matched load for achieving high thermodynamic efficiency in a heat engine. The device proposed exploits this fact by converting thermal energy into kinetic energy of the free piston, and then utilizes this stored kinetic energy to compress and pump air on the opposite side of the piston toward the end of the stroke.

Images

Prototype 3 with Pencil

Prototype 3

Prototype 3 on Breadboard

Prototype 3 Components

Prototype 3 Separated Combustion Chamber

Prototype 3 Reservoir Side Check Valve

Prototype 3 Pump Chamber

Prototype 3 Combustion Valve Seat Jig

Prototype 3 Combustion Valve Seat Machining

Prototype 3 Combustion Valve Back End

Prototype 3 Combustion Valve Test Setup

Prototype 3.5 Design (Abandoned)

Prototype 3.5 Photo (Abandoned)

Prototype 4 High Inertance Liquid Piston Design

Prototype 3.5 and 4 Check Valve Design

Prototype 3.5 and 4 Check Valve Open

Prototype 3.5 and 4 Check Valve Closed

Prototype 3.5 and 4 Check Valve Poppet

Prototype 4 Combustion Section

Prototype 4 on Compact Rescue Crawler

Prototype 1

 

Video


Combustion Valve

Both Valves

Liquid Piston

Prototype 1

Slow Motion Valve

Silicone Piston

Fatigue Testing

Prototype 0

 

Posters